Updated readme regarding dir feature

README.md

@@ -31,3 +31,17 @@ Enable your Golang applications to self update.  Inspired by Chrome based on Her
     go-selfupdate myapp 1.2
 
 This will create a folder in your project called, *public* you can then rsync or transfer this to your webserver or S3.
+
+If you are cross compiling you can specify a directory:
+
+    go-selfupdate /tmp/mybinares/ 1.2
+
+The directory should contain files with the name, $GOOS-$ARCH. Example:
+
+    windows-386
+    darwin-amd64
+    linux-arm
+
+If you are using [goxc](https://github.com/laher/goxc) you can output the files with this naming format by specifying this config:
+
+    "OutPath": "{{.Dest}}{{.PS}}{{.Version}}{{.PS}}{{.Os}}-{{.Arch}}",